Plum Tree Named &#39;Waplumone&#39;

ABSTRACT

A new and distinct variety of plum tree ( Prunus salicina ), which is denominated varietally as ‘Waplumone’, and which produces an attractively colored red-fleshed, freestone plum which is mature for harvesting and shipment approximately July 2 to July 12 under the ecological conditions prevailing in the San Joaquin Valley of central California.

Botanical designation: Prunus salicina.

Varietal denomination: ‘Waplumone’.

BACKGROUND OF THE NEW VARIETY

The present variety of plum tree resulted from an on-going program of fruit tree breeding. The purpose of this program is to improve the commercial quality of deciduous fruit varieties, and rootstocks, by creating and releasing promising selections of Prunus species. To this end we make both controlled and hybrid cross pollinations each year to produce seedling populations from which improved progenies are evaluated and selected.

The seedling, ‘Waplumone’ was originated by the breeders at Wawona Packing Company and selected from a population of seedlings growing in our experimental orchards located near Fowler, Calif. The seedlings, from which the current variety was derived were grown on their own roots, derived from planting seed of ‘Wickson’ plum, which was used as the female parent. The pollen parent of this seedling is unknown. The resulting fruit was collected from the female parent at a mature stage, and seeds were extracted in August of 1998. After a period of stratification, the seed was placed in the greenhouse by population and then field planted for tree establishment and ultimately to exhibit fruit for evaluation. One red-fleshed plum seedling, which is the present variety, exhibited especially desirable characteristics and was then designated as ‘D54.064’. This seedling was marked for subsequent observation. After the 2003 fruiting season, the new variety of plum tree was selected for advanced evaluation and repropagation.

ASEXUAL REPRODUCTION

Asexual reproduction of this new and distinct variety of plum tree was accomplished by budding the new plum tree onto 30 trees of ‘Nemaguard’ Rootstock (unpatented). This was performed by us in our experimental orchard which is located near Fowler, Calif. Subsequent evaluations of these asexually reproduced plants have shown those asexual reproductions run true to the original tree. All characteristics of the original tree and its fruit were established and appear to be transmitted through these succeeding asexual propagations.

SUMMARY OF VARIETY

‘Waplumone’ is a new and distinct variety of plum tree, which is considered of medium sized fruit, and which has a moderately vigorous growth characteristic. This new tree is also a regular and productive bearer of relatively firm, red-fleshed, medium acid, and freestone fruit that have a very good flavor and eating qualities.

This new plum tree has a medium chilling requirement of approximately 500 hours and further produces relatively uniformly sized fruit throughout the tree's canopy. In addition to the foregoing, the fruit of the new plum also appears to have good handling and shipping qualities. The ‘Waplumone’ plum tree bears fruit which are typically ripe for commercial harvesting and shipment on approximately July 2 to July 12 under the ecological conditions prevailing in the San Joaquin Valley of central California. In relative comparison to the ‘Wickson’ plum tree (Luther Burbank introduction 19th century), which is the seed parent the present variety, ‘Waplumone’ ripens approximately 10 to 14 days earlier than the ‘Wickson’ plum tree. Further, the current variety produces fruit that is firmer and more uniformly shaped and exhibits approximately 5.0 to 7.0 brix higher than the ‘Wickson’ plum. Further the flesh color of ‘Waplumone’ is considered red while the seed parent ‘Wickson’ exhibits yellow flesh color.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing, which is provided, is a color photograph of four whole mature fruit harvested, from a tenth leaf tree displaying both the apical and basal fruit aspects. As shown in the photograph, one mature fruit is bisected transversely through the sagittal plane, which reveals the flesh color (see top fruit). Three fruit are also shown to display the apical aspect (second fruit from the top), the basal aspect (third fruit from the top), and the basal aspect with cutin (bloom) removed (bottom fruit). The external coloration of the fruit as shown in the photograph is sufficiently matured for harvesting and shipment. Additionally, the photograph displays a sample vegetative shoot bearing typical leaves and a typical stone with the flesh removed. The colors in these photographs are as nearly true as is reasonably possible in a color representation of this type. Due to chemical development, processing and printing, the leaves and fruit depicted in these photographs may, or may not, be accurate when compared to the actual specimen. For this reason, future color references should be made to the color plates (Royal Horticultural Society, Fourth Edition, 2001) and descriptions provided, hereinafter.

NOT A COMMERCIAL WARRANTY

The following detailed description has been prepared to solely comply with the provisions of 35 U.S.C. § 112 and does not constitute a commercial warranty (either expressed or implied) that the present variety will in the future display all the botanical, pomological, or other characteristics as set forth hereinafter. Therefore, this disclosure may not be relied upon to support any future legal claims including, but not limited to, breach of warranty of merchantability, fitness for any purpose, or non-infringement which is directed, in whole or in part, to the present variety.

DETAILED DESCRIPTION

Referring more specifically to the pomological details of this new and distinct variety of plum tree, the following has been observed during the tenth fruiting season and under the ecological conditions prevailing at the orchards of the assignee, which are located near the town of Fowler, county of Fresno, state of California. All major color code designations are by reference to the R.H.S. Colour Chart (Royal Horticultural Society, Fourth Edition, 2001) provided by The Royal Horticultural Society of Great Britain. Common color names are also occasionally used.

-   Tree:     -   -   Size.—Generally considered medium in its growth pattern as             compared to other common commercial plum cultivars ripening             in the late season of maturity. The tree of the present             variety was pruned to a height of about 250.0 cm to about             300.0 cm at commercial maturity. Fruit size can vary with             crop load and the conditions under which the fruit and tree             are grown.         -   Width.—Approximately 290.0 cm.         -   Vigor.—Considered moderately vigorous. The present plum tree             variety grew from about 135.0 cm to about 150.0 cm in height             during the first growing season. The new variety was pruned             to a height of approximately 150.0 cm during the first             dormant season, and primary scaffolds were then selected for             the desired tree structure.         -   Productivity.—Productive. Fruit set generally varies from             more than the desired crop load to levels much higher than             desired amounts when the new variety is grown in a suitable             horticultural zone when a compatible, coincident pollen             source is provided and under appropriate commercial             conditions. The fruit set is spaced by thinning to develop             the remaining fruit into the desired market-sized fruit. The             number of the fruit set varies with the prevailing climatic             conditions and the cultural practices employed.         -   Fruit bearing.—Regular. Fruit set has been more than             adequate during the previous years of observation, and             thinning was necessary during the past 8 years on both the             original seedling and on subsequent asexually reproduced             trees.         -   Tree form.—Upright and slightly spreading when pruned into a             vase shape.         -   Density.—Considered moderately dense.         -   Hardiness.—The present tree was grown and evaluated in USDA             Hardiness Zone 9. The calculated winter chilling             requirements of the new tree is approximately 500 hours at a             temperature below 7.0 degrees C. The present variety appears             to be hardy under typical central San Joaquin Valley             climatic conditions. -   Trunk:     -   -   Diameter.—Approximately 24.0 cm in diameter when measured             approximately 15.5 cm above the soil level. This measurement             was taken at the beginning of the 8th growing season.         -   Bark texture.—Considered moderately rough with folds of             papery scarfskin being present.         -   Lenticels.—Numerous flat, oval lenticels are present. The             lenticels range in size from about 2.5 mm to about 4.5 mm in             width and between about 1.0 mm and about 2.0 mm in height.             The development and size of the trunk lenticels can be             influenced, to some degree, by the ambient growing             conditions and are not, necessarily, a dependable             characteristic of this variety. As trees of this variety             mature, lenticels are present, but they are generally             covered by increasing layers of cork (mature bark) and             therefore become less apparent with advancing tree maturity.         -   Lenticel color.—Considered an orange brown (RHS             Greyed-Orange Group 165 B).         -   Bark coloration.—Variable, but it is generally considered to             be a greyed silver (RHS Greyed-Green Group 198 A). -   Branches:     -   -   Size.—Considered medium large for the variety.         -   Diameter.—Average as compared to other plum varieties. The             branches have a diameter of about 12.0 cm when measured             during the 8th year after grafting.         -   Flowering shoot thickness.—Average for the species.             Generally, the most consistent flower bud development and,             therefore, potential fruiting sites occur occasionally on             annual shoots which are about 9.0 mm in diameter or larger,             but the vast majority of the fruit is borne on 2 to             5-year-old spurs.         -   Surface texture.—Average and appearing relatively smooth but             with more furrowing on wood which is several years old.             Lenticels are very prevalent within the internodal margins.         -   Crotch angles.—Primary branches are considered variable and             are usually growing at an angle of about 45 degrees when             measured from a horizontal plane.         -   Current season shoots.—Surface texture — Substantially             glabrous.         -   Internode length.—Approximately 2.5 cm to approximately 3.0             cm.         -   Color of mature branches.—Approximately Greyed Green (RHS             Greyed-Green Group 198 C).         -   Current season's shoots.—Color. — Pinkish green (RHS             Greyed-Orange Group 176 C). -   Leaves:     -   -   Size.—Considered somewhat broad for the species. Leaf             measurements have been taken from vigorous, upright,             current-season growth at approximately mid-shoot.         -   Leaf length.—About 95.0 mm to about 110.0 mm (including the             petiole).         -   Leaf Width.—About 45.0 mm to about 50.0 mm.         -   Leaf base-shape.—The leaves generally exhibit unequal             marginal symmetry relative to the leaf longitudinal axis.         -   Leaf form.—Lanceolate.         -   Leaf tip form.—Acuminate.         -   Leaf color.—Upper Leaf Surface — Medium green (approximately             RHS Green Group 137 C).         -   Leaf texture.—Upper Leaf Surface — Glabrous. Lower Leaf             Surface — Glabrous.         -   Leaf color.—Lower Leaf Surface — Deep green (approximately             RHS Green Group 136 B).         -   Leaf venation.—Pinnately veined.         -   Mid-vein.—Color — Considered a pinkish brown (approximately             RHS Greyed-Purple Group 185 D).         -   Leaf margins.—Gently undulating. Form. — Considered             crenulate. Uniformity. — Generally uniform.         -   Leaf petioles.—Form. — Considered canaliculated and having a             more pronounced trough when viewed from the dorsal aspect.             The petiole margin is considered rounded when viewed from             the ventral aspect. Size. — Considered medium large for the             species. Length. — About 9.0 mm to about 12.0 mm. Diameter.             — About 2.0 mm. Color. — A greenish pink (approximately RHS             Greyed-Purple Group 182 C). Texture. — Glabrous. Strength. —             Durable for species until senescence.         -   Leaf glands.—Size. — Considered relatively small for the             species; approximately 1.5 mm in width and about 1.5 mm in             height. Number. — Generally, one or, less commonly, two             glands per marginal side are found. Observations of more             than two glands per marginal side are very uncommon. Type. —             Glands located at or near the base of the leaf are             predominantly globose in shape. Color. — Considered a             yellowed green (approximately RHS Yellow-Green Group 151 A).             Typically, the coloration of the glands darkens and             occasionally begins to desiccate relatively early in the             growing season.         -   Leaf stipules.—Size. — Medium large for this variety with a             length of about 8.0 mm to about 12.0 mm and a width of about             1.5 mm. Number. — Typically, 2 per leaf bud and occasionally             from 4 to 6 per shoot tip. Form. — Lanceolate in form and             having a serrated marginal edge. Color. — Green             (approximately RHS Green Group 137 C) when young, but             graduating to a brown color (approximately RHS Greyed-Orange             Group 165 A) with advancing senescence. The leaf stipules             are generally considered to be early deciduous. -   Flower buds:     -   -   Hardiness.—No winter injury (floral bud death) has been             noted during the last several years of observation in the             central San Joaquin Valley. The new variety of plum tree has             not been intentionally subjected to drought, cold, or heat             stress and, therefore, information regarding these traits is             not available.         -   Flower bud.—Size — Variable, medium small dependent on the             state of maturity. The flower buds as described were             observed approximately 7 days prior to bloom. Length —             Approximately 7.0 mm to approximately 9.0 mm. Diameter —             Approximately 6.0 mm. Surface Texture. — Pubescent.             Orientation. — Considered appressed but appear less so as             the blossoms near opening.         -   Bud scale color.—Approximately RHS Greyed-Orange Group 177             B. -   Flowers:     -   -   Date of first bloom.—Observed on Feb. 23, 2019. Blooming             Time. — Considered average to slightly early mid-bloom in             relative comparison to other commercial plum cultivars grown             in the central San Joaquin Valley. The date of full bloom             was observed on Feb. 28, 2019. The date of full bloom varies             slightly with climatic conditions and prevailing cultural             practices. Duration of Bloom. — Approximately 12 or more             days. This characteristic varies slightly with the             prevailing climatic conditions.         -   Flower class.—Considered a perfect flower, complete and             perigynous.         -   Flower type.—The variety is considered to have a showy type             flower. Flower Size. — Considered medium for the species.             The flower diameter at full bloom is approximately 30.0 mm             to approximately 32.0 mm.         -   Bloom quantity.—Considered abundant.         -   Flower bud density.—Generally considered dense. Flower Bud             Frequency. — Generally, two flower buds appear per node and,             occasionally, one flower bud per node is observed. Multiple             flower buds are present on mature fruiting spurs.         -   Petal size.—Generally considered medium for the species.             Petal Length. — Approximately 12.0 mm to approximately             15.0 mm. Petal Width. — Approximately 9.0 mm to             approximately 11.0 mm.         -   Petal form.—Considered ovate.         -   Petal count.—Nearly always 5.         -   Petal texture.—Upper Petal Texture. — Very finely pubescent,             satin like. Lower Petal Texture. — Very finely pubescent,             satin like.         -   Petal color.—Considered a bright white at the popcorn stage             and throughout the bloom period (RHS White Group 155 D).         -   Fragrance.—Slight.         -   Petal claw.—Form. — The claw is considered ovate and is             generally large relative to the petal size. Length. —             Approximately 10.0 mm. Width. — Approximately 5.0 mm.         -   Petal margins.—Generally, slightly undulate.         -   Petal apex.—Entire.         -   Flower pedicel.—Length. — Considered medium with an             approximate length of about 1.5 mm to about 2.5 mm.             Diameter. — About 1.0 mm to about 1.5 mm. Color. — A medium             brown (approximately RHS Greyed-Orange Group 177 C)             depending on pedicel and fruit maturity and timing of visual             observance. Strength. — Tenacious. Average for the species.             Texture. — Generally smooth to slightly undulate.         -   Floral nectaries.—Color. — Considered a pale green             (approximately RHS Yellow-Green Group 145 B).         -   Calyx.—Surface Texture. — Generally glabrous. Color. —             Approximately RHS Yellow-Green Group 145 A.         -   Sepals.—Upper Surface Texture. — Moderately pubescent,             Satiny. Lower Surface Texture. — Glabrous. Number. — 5             sepals. Size. — Considered medium. Sepal Length. —             Approximately 4.0 mm to approximately 5.0 mm. Sepal Width. —             Approximately 3.0 mm. Sepal Shape. — Generally obovate.             Sepal Margin. — Considered smooth and entire. Sepal Color. —             Approximately RHS Yellow-Green Group 145 A.         -   Anthers.—Generally. — Average in size with a length of about             1.0 mm, a width of about 0.75 mm, and a depth of about             0.5 mm. Color. — White (approximately RHS White Group 155             D). Position Relative to Stigma. — Generally, the stigma is             superior to the anthers by about 1.0 mm to about 2.0 mm.             Position Relative to Petals. — At flower maturity, the             stamens grow to be approximately 4.0 mm to approximately 6.0             mm superior to the base of the petals.         -   Pollen production.—Pollen is abundant and has a yellow color             (approximately RHS Yellow-Orange Group 17 C).         -   Fertility.—Self-unfertile. Pollen allele grouping D2-D7             according to one allele classification test. Prospective             Prunus salicina plum varieties as pollinators could be Santa             Rosa, Primetime, Fortune, Golden Japan.         -   Filaments.—Size. — Approximately 8.0 mm to approximately             10.0 mm in length. Color. — Considered a light greenish             white (RHS Yellow-Green Group 145 D).         -   Pistil.—Number. — Usually one and, only rarely, more than             one. Generally. — Considered medium in size. Length. —             Approximately 9.0 mm to about approximately 12.0 mm in             length including the ovary. Ovary. — Glabrous. Color. —             Considered a very pale green (approximately RHS Yellow-Green             Group 149 C). Surface Texture. — The variety has a long             glabrous pistil. -   Fruit:     -   -   Maturity when described.—Firm ripe condition (shipping             ripe).         -   Date of first picking.—Approximately Jul. 2, 2019.         -   Date of last picking.—Jul. 12, 2019. The date of harvest can             vary with the prevailing climatic conditions, crop loads,             and the current climatic and cultural practices.         -   Size.—Generally — Considered medium to medium small.         -   Average cheek diameter.—About 45.0 mm to about 58.0 mm.         -   Average axial diameter.—About 43.0 mm to about 55.0 mm.         -   Typical weight.—Approximately 165.0 grams. The fruit size             and weight can vary and are dependent on the prevailing             cultural practices and growing conditions and, therefore,             are not particularly distinctive of the new variety.         -   Fruit soluble solids.—Approximately 22.0 degrees Brix to             approximately 27.0 degrees Brix. Fruit sugar levels can vary             significantly depending on fruit maturity and local and             seasonal climatic conditions.         -   Fruit firmness.—Fruit flesh pressures generally averaged             12.0 pounds (about 5.44 kg) at the time the fruit was             analyzed.         -   Titratable acidity.—Approximately 0.5 to approximately 0.6             at commercial harvest maturity.         -   Fruit form.—Generally — Considered oblate. The fruit is             generally very uniform in symmetry.         -   Mucron tip.—Absent.         -   Fruit suture.—No stitching exists along the suture line.         -   Suture.—Color — Generally, the fruit appears blushed to the             same degree as the skin (as described below).         -   Ventral surface.—Form — Considered even and uniform in             appearance when it is viewed from the lateral, sutural             plane.         -   Apex.—Shape — Rounded to slightly retuse.         -   Base.—Shape — Generally smooth and slightly retuse.         -   Stem cavity.—Generally — It extends in a rounded circular             form which is generally considered uniform. The stem cavity             is rounded but slightly extended toward the suture. The             average depth of the stem cavity is about 5.0 mm to about             7.0 mm. The average width of the stem cavity is about             12.0 mm. The average length of the stem cavity, when             measured in the sutural plane is about 14.0 mm.         -   Fruit skin.—Thickness. — Considered medium in thickness, and             tenacious to the flesh. Surface Texture. — Glabrous.             Abundant smooth lenticels are present under the skin             surface. Taste. — Non-astringent. Tendency to crack. —             Radial cracking can be observed over the shoulders of the             fruit at very high maturities or if fruit is subjected to             rainfall when nearing harvest maturity. Lenticels. —             Subcutaneous lenticels are present and are more numerous in             the basal hemisphere. The lenticels are smooth and generally             do not protrude through the fruit surface until fruit             maturity is well past commercial harvest conditions.         -   Fruit skin color.—.         -   Fruit color.—Generally speaking, the color of the fruit skin             is mottled. A golden green ground color is the overall             ground color (described below) with sections of a dull             reddish hue (described below) present throughout the fruit             skin surface, but often more present on the surface that is             more exposed to sunlight. Fruit color would most resemble             the ‘Mariposa’ plum (Luther Burbank introduced from Japan,             1885).         -   Blush color.—It exhibits a mixture of a dull red blush             (approximately RHS Greyed-Red Group 178 B) more typically             present on the portions of the fruit facing the sunlight.             The blush of the fruit typically covers approximately 25% to             approximately 45% of the fruit skin surface. The percentage             of the blush on the fruit skin surface can vary and is             generally dependent upon the fruit's exposure to direct             sunlight, specific fruit maturity, and the prevailing             ecological and cultural conditions under which the fruit was             grown.         -   Ground color.—A greenish-golden (approximately RHS             Yellow-Green Group 155 C).         -   Fruit glossiness.—Fruit considered to be moderately glossy             with a heavy bloom (cutin) layer covering the surface.         -   Fruit stem.—Size. — Medium in length, about 6.0 mm to about             8.0 mm. Diameter. — About 2.0 mm to about 3.0 mm. Color. —             Pale yellow green (approximately RHS Yellow-Green Group N144             B).         -   Fruit flesh.—Ripening. — Considered even. Texture. — Firm,             crunchy, juicy and dense. Considered non-melting in flesh             classification. Fibers. — Present but not prominent. Aroma.             — Slight. Eating Quality. — Considered Excellent. Flavor. —             Excellent, complex flavor. Considered balanced with             sweetness and acidity. Juice Production. — High. Brix. —             About 22.0 degrees to about 27.0 degrees. This             characteristic varies slightly with the number of fruits per             tree, fruit position on the tree, the maturity of fruit when             harvested, the prevailing cultural practices, and the             ambient climatic conditions. Acidity. — Considered medium.             Approximately 0.5 to approximately 0.6 titratable acidity at             fruit harvest. Acid levels assayed from fruit flesh can vary             with fruit maturity, length of time in cold storage,             sunlight exposure, and climatic, regional, seasonal, and             cultural influences. Flesh Color. — It is considered pinkish             white (approximately RHS Greyed-Red Group 180 C) to a deeper             reddish color (approximately RHS Greyed-Red Group 181 A)             when observed closer to fruit maturity. -   Stone:     -   -   Type.—Considered a tight freestone.         -   Size.—It is generally considered to be medium small for the             species. The stone size varies significantly depending upon             the tree vigor, the crop load, and the prevailing growing             and cultural conditions under which the tree was grown.         -   Length.—Average, about 18.0 mm to about 21.0 mm.         -   Width.—Average, about 16.0 mm to about 18.0 mm.         -   Diameter.—Average, about 8.0 mm to about 12.0 mm.         -   Form.—Roughly ovoid.         -   Stone base.—Shape — The stone is considered ovoid.         -   Apex.—Shape — The stone often exhibits a reasonably small             acute tip.         -   Stone surface.—Surface Texture — Considered relatively             smooth. Ridges. — Surface ridging is generally not present.             Ventral Edge. — The ventral edge is generally is described             as having adjoining ridges formed from each hemisphere and a             more prominent ridge in the ventral suture margin. Dorsal             edge .— Shape — Generally considered even without ridging.         -   Stone color.—The color of a mature, dry stone is generally             considered a pale light brown (approximately RHS             Yellow-White Group 158 A).         -   Tendency to split.—Splitting has rarely been noted.         -   Kernel.—Length. — Approximately 12.0 mm to approximately             15.0 mm. Width. — Approximately 14.0 mm to approximately             16.0 mm. Thickness. — Approximately 4.0 mm to approximately             6.0 mm. Size. — The kernel is considered medium small. Form.             — Considered generally ovoid to rounded in shape. Kernel             Surface Texture. — Kernel pellicle is shortly pubescent.             Color. — A dark tan (RHS Greyed-Orange Group 164 B).         -   Use.—The present variety ‘Waplumone’ is considered to be a             plum tree of early mid-season of maturity, which produces             fruit which are considered to be firm, attractively colored,             and useful for both local and long-distance shipping.         -   Keeping quality.—Appears excellent. The fruit of the present             variety has stored well for periods of up to 30 days after             harvest at 1.0 degree Celsius.         -   Shipping quality.—Good. The fruit of the new plum tree             variety showed minimal bruising of the flesh or skin damage             after being subjected to normal harvesting and packing             procedures.         -   Resistance to insects and disease.—No susceptibilities were             noted. The present variety has not been intentionally tested             to expose or detect any susceptibilities or resistances to             any known plant, fruit diseases, insect, frost, winter             injury, or other environmental factors. Although the new             variety of plum tree possesses the described characteristics             when grown under the ecological conditions prevailing near             Fowler, Calif., in the Central part of the San Joaquin             Valley of California, variations of the usual magnitude and             characteristics incident to changes in growing conditions,             fertilization, nutrition, pruning, pest control, frost,             climatic variables, and changes in horticultural management             are to be expected. 

Having thus described and illustrated our new variety of plum tree, what we claim is new, and desire to secure by plant Letters Patent is:
 1. A new distinct variety of plum tree substantially as illustrated and described, and which is characterized principally as to novelty by producing an attractively colored red-fleshed, freestone plum which is mature for harvesting and shipment approximately July 2 to July 12 under the ecological conditions prevailing in the San Joaquin Valley of central California. 